| 摘要 |
PURPOSE:To record information at both faces by laminating high and low refraction factor layers so as to constitute a plane waveguide path and further laminating a diffusion layer and a recording one thereon. CONSTITUTION:On a substrate 1, a lower side clad layer 2, a core layer 3 and a defective part 4 are formed, and on the core layer 3 a transmittable upper side clad layer 5 is laminated. When an irradiated light beam condensed on the end face of the core layer 3 from the side of a card-like recording medium 11 is made incident, the light beam incident on the core layer 3 transfers heat inside the layer due to total reflection, and the light beam for reaching the defective part 4 of the core layer 3 passes through the upper side clad layer 5 and is diffused by a light diffusion layer 6. The distribution state of the defective part 4 of the core layer 3 and the thickness of the diffusion layer 6 are appropriately controlled, whereby a planal light source for making the entire recording area approximately uniform can be constituted. The light beam from said light source transmits a write bit 10, and therefore the presence or absence of the bit 10 can be read by any of a photodetecting means from the surface of the card. Thus information can be recorded at both faces. |
